Increased Expression of the lncRNA NRON Along With NFATc1/PIM-1 in Labial Salivary Glands of Sjögren’s Syndrome Patients

The aim of our study was to analyze the expressions of nuclear factor of activated T cells (NFAT)-related substances including long noncoding RNA NRON which participates in pathophysiology of Sjögren’s syndrome (SS), and to assess the histologic findings in individuals with SS. In this study, the expressions of NRON, NFATc1, CD3/CD4, and proviral integration site for Moloney murine leukemia virus (PIM)-1 were examined by in situ hybridization, immunohistochemical analysis, and immunofluorescence in labial salivary glands (LSGs) obtained from 16 patients with SS and five controls. The microcell count method has been applied to calculate the NFATc1-positive area/infiltrating cell area in LSGs, and we compared those results to the infiltrating cell area, focus score, serum immunoglobulin G, and the European League Against Rheumatism Sjögren’s Syndrome Disease Activity Index. The NRON expression in the nuclei of cell-infiltration lesions of the SS patients were prominent. The NFATc1 expression was strong in the cytoplasm of infiltrating mononuclear cells and weak in ducts of both SS and controls. In SS, the NFATc1-positive area/infiltrating cell area was positively correlated with the infiltrating cell area and focus score. CD3/CD4 was expressed in infiltrating mononuclear cells, and PIM-1 colocalized with NFATc1 in the cytoplasm. These results suggest NRON along with NFATc1/PIM-1 in SS LSGs might participate in SS pathophysiology.